Skeletal Muscle Prime mover (agonist) Antagonist Synergist Fixators

Naming of Skeletal Muscles Location of muscle Shape of muscle Size of muscle Direction of fibers # of origins Location of attachments Action

Muscle Mechanics Arrangement of fascicles Lever Systems Circular, pennate, parallel, convergent Lever Systems Mechanical advantage – moving large load over a small distance with little effort (power lever) Mechanical disadvantage – effort exerted greater than load (speed lever) 1st - seesaws – effort (tension) at one end, load at other, fulcrum in middle, 2nd - effort and fulcrum at ends, load in middle, 3rd class – great speed – effort between load and fulcrum

Facial Muscles

Neck Muscles Sternocleidomastoid – PM head flexion Scalenes – flexion and rotation Splenius – extend or hyperextend (posterior neck)

Back Extensors Erector spinae Semispinalis Quadratus lumborum

Breathing Diaphragm External intercostals – inspiration Internal intercostals - expiration

Compression of Abdomen External obliques, internal obliques, transversus abdominis Rectus abdominis Valsalva maneuver – abdominal muscles contract, along with diaphragm; glottis closed

Pelvic Floor and Perineum Levator ani Coccygeus External anal sphincter External urethral sphincter Ischiocavernosus Bulbospongiosus

Shoulder movements Pectoralis minor Serratus anterior Subclavius Trapezius Levator scapulae Rhomboids

Arm Movements Pectoralis major Latissimus dorsi Deltoid Subscapularis Supra- and infraspinatus Teres major and minor Coracobrachialis